1. Field of the Invention
The system of the present invention relates to oil/water separators. More particularly, the apparatus of the present invention relates to an oil/water separator wherein a continuous flow of oil and/or suspended particulates ladened water is circulated through a plurality of aeration cells with clean water effluent recirculated to each aeration cell, educting gas into the suspension for floatation and collecting contaminants in a suspended oil ladened froth layer and siphoning off the contaminants during the process.
2. General Background
In many industries, particularly the oil and gas industry, there is an ever present problem of contaminated water as one of the by-products of process. For example, on an oil and gas producing platform, water that has been produced from the well, often is resultantly ladened with oil, and/or suspended solids, therefore, cannot be simply disposed of in the surrounding water, due to the oil and solids contaminants. That being the case, there has been a successive development of apparatuses and systems which attempt to remove oil and solids from the water to a degree that it is relatively safe for return into the surrounding sea.
In the present state of the art, U.S. Filter Corporation manufactures a device which mixes and disburses gas in the form of fine bubbles in the body of liquid in a tank for attempting to remove contaminants from flowing water. This apparatus is covered by U.S. Pat. No. 4,255,262, which employs a gas induction from the upper section of the respective tanks downward via a draft tube to the liquid body contained within the tank. The gas induction occurs as a given portion of the liquid portion already contained in the vessel is recirculated back through the individual cells or compartments with a centrifugal pump. The apparatus also utilizes a mechanical skimmer assembly, electrically driven, which serves to remove the impurity ladened froth from above the liquid level section of the tank. Such skimmers are moderate to high maintenance components of a separation system particularly in such corrossive environments as the oil producing and chemical plant industry.
Another shortcoming of the system under '262 patent are the rectangular-shaped tanks which cannot, by virtue of their construction, withstand pressures in excess of 2 ounces per square inch internal. This is a particular disadvantage especially where system pressure upstream of the oil/water separator are prevalent or where noxious or lethal gases such as hydrogen sulfide are present. Also, the retangular tanks having the skimmers are limited in volumetric capacity merely because full utilization of the tank is not allowed. Construction costs for this particular style tank is relatively high due to bending and welding required to shape the tank to the rectangular configuration. Although such tanks are described as "gas tight," gas pressures are maintained by continuously venting the gas to atmosphere, therefore not truly being "gas tight."
Other patents which were found as a result of a search of the art, but may not be particularly relevant are as follows:
U.S. Pat. No. 2,274,658 issued to R. B. Booth PA1 U.S. Pat. No. 2,782,929 issued to W. W. Colket PA1 U.S. Pat. No. 3,468,421 issued to B. S. Hazel, et al PA1 U.S. Pat. No. 1,648,558 issued to J. R. Mesten, et al PA1 U.S. Pat. No. 1,612,557 issued to E. C. Wiseburger PA1 U.S. Pat. No. 911,314 issued to H. F. Maryville PA1 U.S. Pat. No. 2,825,422 issued to O. B. Showenfeld PA1 U.S. Pat. No. 4,305,819 issued to Kobozev, et al PA1 U.S. Pat. No. 2,942,733 issued to H. A. Thompson PA1 U.S. Pat. No. 2,179,131 issued to R. B. Miller PA1 U.S. Pat. No. 4,102,787 issued to A. A. Gersten PA1 U.S. Pat. No. 4,147,629 issued to A. A. Gersten PA1 U.S. Pat. No. 4,111,806 issued to Wright, et al